Power Quality Improvement Using Series Active Power Filter Based On Gravitational Search Algorithm

This paper proposes a heuristic control of the series active power filter for power quality enhancement. In this context, the series active filter is better utilized as a voltage source controller contrary to its conventional usage as variable impedance. The present-day utility system as a linear model is unsatisfactory and the steps are laid down to discuss utility system as a nonlinear model. This paper deals power quality disturbances like voltage sag/swell, voltage error and THD with robust heuristic algorithms like the gravitational search algorithms (GSA) and it is further compared with firefly (FF) algorithm. The harmonic reduction in the source current and mitigation of sags/swells in the load voltage is carried out with optimal tuning of the PI controller. The series active power filter as a harmonic suppressor with a specific reference controlled strategy is discussed in this paper. The synchronous reference frame (SRF) theory is used to generate the reference voltage signals required for compensation. The hysteresis band current controller (HBCC) is used to perform the switching operation of Voltage Source Inverter. Simulations are carried out in the MATLAB/SIMULINK environment

Power Quality Improvement Based On PSO Algorithm Incorporating UPQC

The usage of the term power quality is increasing day by day with extensive usage of large capacity loads and nonlinear loads. The major power quality issues are voltage disturbances and current disturbances in the present-day power systems. Today, with the advent of power semiconductor devices these power quality issues are solved to a great extent. The unified power quality conditioner is one such power semiconductor device which utilizes active filtering methodology to deal with the concerned power quality issues. Here an attempt is made to control and generate the reference currents and voltages for a unified power quality conditioner with the optimal tuned synchronous reference frame theory. The particle swarm optimization is employed to evolve gains of the proportional-integral controller. The unified power quality conditioner is a combination of shunt and series voltage source converters. The hysteresis band current controller for series and the pulse width modulation current controller for the shunt active filter are used for generation of gating pulses required by the switches of the voltage source converters in the unified power quality conditioner. The performance evaluation of multi-objective convergence fitness function (dealing: the voltage sag, the source current variations, and the load voltage variations) with unified power quality conditioner based on particle swarm optimization algorithm is performed. The efficacy of the proposed work is validated by conducting simulations in MATLAB/SIMULINK software environment.

An Economic Assessment along the Jatropha-based Biodiesel Value Chain In India

The Government of India had launched the National Biofuel Mission in the year 2003 as an initiative to limit the country’s dependence on crude oil imports. An integral part of this mission is the Biodiesel Blending program and Jatropha, a tree-borne biodiesel yielding crop, is the cornerstone of the program. This study has been specifically designed to carry out economic assessment of the upcoming jatropha-based biodiesel value chain in the country. The study, based on primary data collected from three major jatropha growing states, has observed that jatropha cultivation is an economically viable proposition in the long-run as indicated by favourable values of net present value, internal rate of return and benefit cost ratio. Nevertheless, initial government support till attaining break even point is crucial to sustain the interest of the farmers. The jatropha seed processing industry has been found to be viable if operated at sufficient economies of scale, which in turn is determined by the level of backward integration with the seed market and a forward integration with biodiesel distribution channels. However, the existing biodiesel value chain in India lacks this integration and is characterized by under-developed seed markets, sub-optimal processing infrastructure and ill-defined biodiesel distribution channels. The involvement of corporate players to participate in processing and distribution activities has further delayed the program to take off. The study has cautioned that unless proactive orientation of all the stakeholders is ensured, the program may fail to meet its objectives, at least in the medium-term.Agricultural and Food Policy,

Genetic analysis for high temperature tolerance in bread wheat

Heat stress, characterised by a trend in average temperature increase during anthesis and grain filling, leads to forced maturity is one of the major constraints of wheat production in arid and, semiarid regions of the world. This study examined the nature and magnitude of gene action for yield and its contributing characters and some important heat tolerant parameters in bread wheat ( Triticum aestivum l em. thell) to determine breeding strategies for future breeding programmes. Twelve lines and four testers were crossed in an L x T mating design. The 48 crosses and their parents were raised under normal (21, November 2002) and late sown (1, January 2003) seasons at the Experimental Farm of Rajasthan College of Agriculture, Udaipur in India. Lines K\u2019sona, DWR 195, C 306 and K 9708 were found to be good combiners for different heat tolerant parameters along with grain yield. Combinations of Raj 3077 x Kailash under normal (E1) and late sown (E2), C 306 x PBN 51 (E1) and C 306 x HD 2189 (E2) for grain yield; had high sca effect. The crosses viz., K 9708 x PBN 51 for proline content and heat injury, DWR 195 with HD 2189, and C 306 with Kailash for heat injury had desirable significant sca effects. The other crosses, HD 2329 x Kailash for pollen viability, and Raj 3765 x Kailash for chlorophyll content, were the best specific combiners. Parents like C 306, K\u2019sona, DWR 195, K 9708, Raj 3077, PBN 51 and Kailash could be utilised in multiple crossing programmes and further biparental matting for selection of high yielding progenies for heat tolerance.Le stress d\ufb \ue0 la chaleur, caract\ue9ris\ue9 par une tendance \ue0 l\u2019augmentation de la temp\ue9rature moyenne au cours de l\u2019anth\ue9sis et du remplissage de grains, et conduisant \ue0 la maturation forc\ue9e est une des contraintes majeures \ue0 la production du bl\ue9 dans des r\ue9gions arides et semi arides du monde. Cette \ue9tude a examin\ue9 la nature et la magnitude de l\u2019action de g\ue8nes de rendement et ses caract\ue8res contributifs ainsi que quelques param\ue8tres importants de tol\ue9rance dans le bl\ue9 patissier ( Triticum aestivum ) afin de d\ue9terminer des strat\ue9gies d\u2019am\ue9lioration pour des programmes futures d\u2019am\ue9lioration. Douze lign\ue9es et quatre testeurs \ue9taient crois\ue9s en dispositf L x T. Les 48 croisements et leurs parents \ue9taient plant\ue9s en saisons normale (21, November 2002) et tardive (1, January 2003) \ue0 la ferme exp\ue9rimentale du coll\ue8ge d\u2019Agriculture de Rajasthan, Udaipur en Inde. Les lign\ue9es K\u2019sona, DWR 195, C 306 et K 9708 \ue9taient jug\ue9es de bons combinants pour diff\ue9rents param\ue8tres de tol\ue9rance \ue0 la chaleur avec un bon redement en grains. Les combinaisons de Raj 3077 x Kailash en saison normale (E1) et plant\ue9es tardivement (E2), C 306 x PBN 51 (E1) et C 306 x HD 2189 (E2) pour rendement en grain avaient un effet sca \ue9lev\ue9.Les croisements telque K 9708 x PBN 51 avec for proline content and heat injury, DWR 195 avec HD 2189, etC 306 avec Kailash pour dommage de la chaleur avaient d\u2019effects sca significatifs. Les autres croisements, HD 2329 x Kailash pour variabilit\ue9 de pollen, et Raj 3765 x Kailash pour contenu chlorophyllien, \ue9taient les meilleurs combinants sp\ue9cifiques. Les parents dont C 306, K\u2019sona, DWR 195, K 9708, Raj 3077, PBN 51 et Kailash pourraient \ueatre utilis\ue9s dans de multiples programmes de croisement et autres couvertures biparentales pour la s\ue9lection de prog\ue9nies \ue0 rendement \ue9lev\ue9 avec tol\ue9rance \ue0 la chaleur

Incremental proximal methods for large scale convex optimization

Laboratory for Information and Decision Systems Report LIDS-P-2847We consider the minimization of a sum∑m [over]i=1 fi (x) consisting of a large number of convex component functions fi . For this problem, incremental methods consisting of gradient or subgradient iterations applied to single components have proved very effective. We propose new incremental methods, consisting of proximal iterations applied to single components, as well as combinations of gradient, subgradient, and proximal iterations. We provide a convergence and rate of convergence analysis of a variety of such methods, including some that involve randomization in the selection of components.We also discuss applications in a few contexts, including signal processing and inference/machine learning.United States. Air Force Office of Scientific Research (grant FA9550-10-1-0412

Strange particle production in proton-proton collisions at s=0.9\sqrt{s}=0.9 TeV with ALICE at the LHC

The production of mesons containing strange quarks (K$^0_s$, $\phi$) and both singly and doubly strange baryons ($\Lambda$, Anti-$\Lambda$, and $\Xi$+Anti-$\Xi$) are measured at central rapidity in pp collisions at $\sqrt{s}$ = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at central rapidities for inelastic pp collisions are presented. For mesons, we report yields () of 0.184 $\pm$ 0.002 stat. $\pm$ 0.006 syst. for K$^0_s$ and 0.021 $\pm$ 0.004 stat. $\pm$ 0.003 syst. for $\phi$. For baryons, we find = 0.048 $\pm$ 0.001 stat. $\pm$ 0.004 syst. for $\Lambda$, 0.047 $\pm$ 0.002 stat. $\pm$ 0.005 syst. for Anti-$\Lambda$ and 0.0101 $\pm$ 0.0020 stat. $\pm$ 0.0009 syst. for $\Xi$+Anti-$\Xi$. The results are also compared with predictions for identified particle spectra from QCD-inspired models and provide a baseline for comparisons with both future pp measurements at higher energies and heavy-ion collisions.Comment: 33 pages, 21 captioned figures, 10 tables, authors from page 28, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in $|\eta|<0.8$ and $0.3 < p_T < 20$ GeV/$c$ are compared to the expectation in pp collisions at the same $\sqrt{s_{\rm NN}}$, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor $R_{\rm AA}$. The result indicates only weak medium effects ($R_{\rm AA} \approx$ 0.7) in peripheral collisions. In central collisions, $R_{\rm AA}$ reaches a minimum of about 0.14 at $p_{\rm T}=6$-7GeV/$c$ and increases significantly at larger $p_{\rm T}$. The measured suppression of high-$p_{\rm T}$ particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The yield of charged particles associated with high-$p_{\rm T}$ trigger particles ($8 < p_{\rm T} < 15$ GeV/$c$) is measured with the ALICE detector in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jet-like correlation peaks in azimuthal di-hadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta $p_{\rm T}> 3$ GeV/$c$ on the away-side drops to about 60% of that observed in pp collisions, while on the near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/350